共查询到20条相似文献，搜索用时 46 毫秒
1.
温度对不同大小墨西哥湾扇贝生长的影响 总被引：2，自引：0，他引：2
在8—32℃实验室控温范围内以2℃为梯度,以壳高及体重增长作为观察指标,研究3个规格墨西哥湾扇贝Argopecten irradians concentricus的适宜、较适宜及最适宜生长温度。研究结果表明,小苗(壳高6.2mm,体重48.3mg)、中苗(壳高18.1mm,体重1191.1mg)、大苗(壳高30.7mm,体重5809.9mg)在8—32℃水温下均能生长,但在水温8及32℃,3种规格增长率均较低;适宜生长温度分别为小苗11.2—31.1℃、中苗9.8—31.8℃、大苗9.8—32.4℃;较适宜生长温度分别为小苗18.1—29.4℃、中苗18.5—29.4℃、大苗16.9—30.4℃;3种苗随规格增大,适温范围扩大(p<0.01);最适生长温度3种苗均为24—28.0℃,其范围向高温端漂移;在水温为8℃时,3种苗存活率均达到97.0%以上,水温在32℃时则小苗为47.0%、中苗为67.5%、大苗为76.0%,表现出3种苗对低温有更强的忍耐力,大苗对高温有更强的适应性。 相似文献
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台湾东风螺人工繁殖及苗种生物学的初步研究 总被引：1，自引：0，他引：1
对台湾东风螺(Babylonialutosa)进行人工繁育试验。试验结果表明,台湾东风螺亲螺在繁殖初期日摄食量为1.5%以上,最高可达3.0%,但繁殖盛期摄食量减少。在人工饲养条件下,利用水泥方砖采卵效果良好。在水温22.5~25.6℃和充气条件下,台湾东风螺受精卵在卵囊内完成胚胎发育破囊孵出的时间为7d,孵化率为95%以上。在水温为24.0~27.5℃、培育密度为0.10个/mL左右时,幼虫壳长生长速度可达18.1μm/d,其生长曲线显示中后期生长加速,成活率为60%以上;幼虫发育至附着变态的平均时间为22d,在铺砂与不铺砂条件下均可附着变态。在水温为25.1~26.5℃、培育密度为2000~2100个/m2时采用无铺砂培育台湾东风螺稚贝,其壳高由1.3mm长至5.5mm,生长速度为0.22mm/d,成活率为29.5%。 相似文献
3.
胶州湾不同容器与不同密度养殖海湾扇贝的比较 总被引：2，自引：0，他引：2
Ⅰ. 材料与方法 试验用海湾扇贝苗种是1985年春采自于乳山县石埠海珍品养殖试验场。4月底采卵育苗,5月中旬移到海上中间养育,7月8日从乳山运来胶州湾红石崖镇海水养殖场,卵苗平均壳高8mm。8月份长到壳高1.5cm以上时陆续分苗到养成笼中。9月l8日将养成笼中的海湾扇贝(当时约有20—30%的个体仍然附着在底盘上)倒出来,混合均匀,然后按给定的试验密度分装入试验容器中。试验用贝平均壳高27.6mm(22—37mm),平均体重6.7g。 相似文献
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管角螺网笼养殖技术的研究 总被引：1，自引：0，他引：1
研究了网笼吊养模式和饵料对管角螺成活率和生长率的影响。结果表明,2010年7月吊养平均壳高34.02mm、平均体质量2.61g的管角螺苗,至2010年9月30日,平均壳高达51.07mm,平均体质量6.99g。在5种不同放养密度下,以每笼20个生长最快。自2010年7月中旬分笼养成,至每次测量,成活率为98.7%,分笼前成活率96.1%,总成活率94.9%。饵料以双壳贝类为主,小牡蛎(团聚牡蛎)是管角螺网笼养殖的较理想饵料。应加强6～11月管角螺快速生长期的管理 相似文献
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文蛤稚贝盐度适应性的研究 总被引：2，自引：0，他引：2
在室内条件下,观察不同海水盐度对文蛤(Meretrix meretrix Linnaeus)稚贝存活及生长的影响,并将168h50%死亡的盐度作为适宜生存临界盐度,将增长率30%时所对应的盐度作为适宜生长临界盐度。结果表明:在稚贝体重(13.07±3.4)mg、壳长(3.46±0.35)mm、壳高(3.16±0.30)mm,水温27.4℃～29.1℃,pH值7.8～8.2下,文蛤稚贝适宜生存盐度为6.5～39.5,最适生存盐度为9.0～31.0;适宜生长盐度为7.3～38.7,最适生长盐度为15.0～23.0。在最适盐度范围之外,稚贝的存活率、体重、壳高及壳长日增长率均随着盐度的升高或降低而降低。 相似文献
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砗蚝(Hippopus hippopus)的人工繁育 总被引：1，自引：0，他引：1
于2016年4—9月开展了砗蚝(Hippopus hippopus)人工繁育技术研究。采用五羟色胺进行催产、促使配子排放;精卵分别收集,进行异体间受精以避免自交;受精卵经过30h孵化,选出600万D形幼虫进行培育。砗蚝的早期生活史与砗磲(Tridacna spp.)相似,经历前期面盘幼虫、中期面盘幼虫、后期面盘幼虫、足面盘幼虫、单水管稚贝、双水管稚贝、外套膜触手稚贝、幼贝等阶段。与砗磲不同的是,砗蚝怀卵量较少,但卵径较大,D型幼虫也较大,幼虫趋光性更强,壳长2.0mm以后外套膜不伸出壳缘外,幼贝贝壳形态也不同于砗磲。同砗磲幼虫一样,砗蚝幼虫需要构建虫黄藻系统之后,才能出现鳃、次生壳等,从而完成变态成为稚贝。砗蚝幼虫变态率较低,仅为1.4%。中间育成期间,丝状藻和锥形螺是稚贝培育的主要敌害,需及时清理才能确保稚幼贝正常生长发育。经过120d的精心饲育,培养出平均壳长6.3mm幼贝500余个。本研究为进一步开展砗蚝人工繁育、中间育成、增殖放流、资源修复及移植保育提供了参考。 相似文献
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潮间带网箱养鲍技术研究 总被引：1，自引：0，他引：1
本文报道了从１９９３年５月～１９９４年１０月开展潮间带网箱鲍的试验，在选好的岩礁区筑坝建池，防止落潮后网箱干露，利于鲍鱼度夏和越冬，利用网箱养鲍，便于管理，并可防止鲍鱼外逃及敌害生物侵入，苗种壳高２厘米以上，以提高其成活率；放养密度；壳高４厘米以前，每平方米２００～３００只，壳高４厘米以后，每平方米５０～１００只，可利于鲍鱼生长；饵料以海带，裙带菜为主，水温低于８℃时，很少投铒，水温８～１５℃，每 相似文献
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栉孔扇贝不同种群杂交效果的研究 Ⅱ.中国种群和俄罗斯种群及其杂种F1中期生长发育 总被引：1，自引：1，他引：1
在对栉孔扇贝中国养殖种群(CC)、中国野生种群(CW)和俄罗斯种群(RW)及其3 种杂交种群早期(2,3,4月龄)生长发育研究的基础上进行了各种群的中期(6,8,10,12月龄)生长发育测定比较研究,结果表明,3个亲本群体各个性状的中期生长性能表现以中国养殖种群最好;3个杂交组合的杂种群体各个性状的中期生长性能均高于纯种亲本种群,杂种优势均较大,其范围在3%~52%,以CC♀×RW♂杂交效果最好;壳长、壳宽、壳高、活体重在4个生长发育指标中期的4 个阶段均表现出不同程度的杂种优势,杂种优势在性状间存在明显差别,体重的杂种优势远大于壳宽、壳长和壳高的,变化趋势为体重大于壳宽,壳宽大于壳长,壳长大于壳高;季节性变化因素对栉孔扇贝各个性状的生长速度影响非常大,6~8月龄处于冬季最寒冷的时间(11月份至翌年3月份),扇贝越冬期间仅能维持生命,生长率接近于0,温暖季节如6月龄(11月)以前和8月龄(3月份)以后各性状的生长速度提高幅度很大. 相似文献
11.
Chandralata Raghukumar G. Sheelu P. A. Loka Bharathi Shanta Nair C. Mohandass 《Marine Georesources & Geotechnology》2001,19(1):1-16
In order to assess the impact of deep-sea mining on the in situ benthic life, we measured the microbial standing stock and concentration of organic nutrients in the deep-sea sediments of the Central Indian Ocean Basin in the Indian pioneer area. Sediments were collected using box core and grab samples during September 1996. The total bacterial numbers ranged from 10 10 -10 11 cells per g -1 dry weight sediment. There was a marginal decrease in the number of bacteria from surface to 30 cm depth, though the subsurface section registered a higher number than did the surface. The highest numbers were encountered at depths of 4-8 cm. The retrievable number of bacteria were two orders less in comparison with the direct total counts of bacteria. An almost homogeneous distribution of bacteria, total organic carbon, living biomass, and lipids throughout the depth of cores indicates active microbial and benthic processes in the deep sea sediments. On the other hand, a uniform distribution of total counts of bacteria, carbohydrates, and total organic carbon in all the cores indicates their stable nature and suggests that they can serve as useful parameters for long-term monitoring of the area after the benthic disturbance. Further studies on temporal variability in this region would not only verify the observed norms of distribution of these variables but would also help to understand restabilization processes after the simulated benthic disturbance. 相似文献
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Derek V. Ellis 《Marine Georesources & Geotechnology》2001,19(1):51-63
This article reviews information recently available from existing marine and coastal mining for responses to environmental issues affecting marine mining at different depths. It is particularly but not exclusively concerned with those issues affecting seabed biodiversity impact and recovery. Much information has been gathered in the past 10 years from shallow mining operations for construction aggregate, diamonds, and gold, from coastal mines discharging tailings to shallow and deep water, and from experimental deep mining tests. The responses to issues identified are summarized in a series of eight tables intended to facilitate site-specific consideration. Since impacts can spread widely in the surface mixing layer SML, and can affect the biologically productive euphotic zone, the main issues considered arise from the depth of mining relative to the SML of the sea. Where mining is below the SML, the issue is whether it is environmentally better to bring the extraction products to the surface vessel for processing (and waste discharge), or to process the extraction products as much as possible on the seabed. Responses to the issues need to be sitespecific, and dependent on adequate preoperational environmental impact and recovery prediction. For deep tailings disposal from a surface vessel, there are four important environmental unknowns: (1) the possible growth of "marine snow" (bacterial flocs) utilizing the enormous quantities of fine tailings particles (hundreds or thousands of metric tons per day) as nuclei for growth, (2) the possibility that local keystone plankton and nekton species may migrate diurnally down to and beyond the depth of deep discharge and hence be subjected to tailings impact at depth, (3) the burrow-up capability of deep benthos and their ability to survive high rates of tailings deposition, and (4) the pattern and rate of dispersion of a tailings density current through the deep water column from discharge point to seabed. Actions to obtain relevant information in general and site-specifically are suggested. 相似文献
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G. Parthiban 《Marine Georesources & Geotechnology》2000,18(3):223-235
Particle fluxes were measured 7 m above the sea bottom during the predisturbance, disturbance, and postdisturbance periods by using time series sediment traps attached to seven deep-sea moorings deployed in the INDEX experiment site in the Central Indian Basin. The predisturbance particle fluxes varied between 22.3 to 55.1 mg m -2 day -1 . Increased and variable particle fluxes were recorded by the sediment traps during the disturbance period. The increase observed was 0.5 to 4 times more than the background predisturbance fluxes. The increases in particle fluxes (~4 times) recorded by the sediment trap located in the southwestern direction (DMS-1) were the greatest, which could be the result of preferential movement of resuspended particles generated during the deep-sea benthic disturbance along the general current direction prevailing in this area during the experimental period. Also, the traps located closer to the disturbance area recorded greater fluxes than did the traps far away, across the Deep Sea Sediment Resuspension System path. This variability in recorded particle fluxes by the traps around the disturbance area clearly indicates that physical characteristics such as grain size and density of the resuspended particles produced during the disturbance had an important effect on particle movement. The postdisturbance measurements during ~5 days showed a reduction in particle fluxes of ~50%, indicating rapid particle settlement. 相似文献
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Arne Schnack-Friedrichsen Angela M. Davis Jim D. Bennell Dei G. Huws 《Marine Georesources & Geotechnology》2001,19(4):221-243
The interdependence between the seismo-acoustic properties of a marine sediment and its geotechnical/physical parameters has been known for many years, and it has been postulated that this should allow the extraction of geotechnical information from seismic data. Though in the literature many correlations have been published for the surficial layer, there is a lack of information for greater sediment depths. In this article, a desktop study on a synthetic seafloor model illustrates how the application of published near-surface prediction equations to subsurface sediments (up to several tens of meters burial depth) can lead to spurious predictions. To test this further, acoustic and geotechnical properties were measured on a number of sediment core samples, some of which were subjected to loading in acoustically-equipped consolidation cells (oedometers) to simulate greater burial depth conditions. For low effective pressures (representing small burial depths extending to around 10 meters subsurface), the general applicability of established relationships was confirmed: the prediction of porosity, bulk density, and mean grain size from acoustic velocity and impedance appears generally possible for the investigated sedimentary environments. As effective pressure increases through, the observed relationships deviate more and more from the established ones for the near-surface area. For the samples tested in this study, in some instances increasing pressure even resulted in decreasing velocities. There are several possible explanations for this abnormal behavior, including the presence of gas, overconsolidation, or bimodal grain size distribution. The results indicate that an appropriate depth correction must be introduced into the published prediction equations in order to obtain reliable estimates of physical sediment properties for greater subsurface depths. 相似文献
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Geoacoustic Inversion via Genetic Algorithm and Its Application to Manganese Sediment Identification
An acoustic inversion method using a wide-band signal and two near field receivers is proposed and applied to multiple layered seabed models including a manganese sediment. The inversion problem can be formulated into a probabilistic model comprised of signals, a forward model, and additive noise. The forward model simulates wide-band signals, such as chirp signals, and is chosen to be the source-waveletconvolution plane wave modeling method. The wavelet matching technique, using weighted least-squares fitting, estimates the sediment sound-speed and thickness on which determination of the possible numerical ranges for a priori uniform distribution is based. The genetic algorithm is applied to a global optimization problem to find a maximum a posteriori solution for determined a priori search space. Here the object function is defined by an L 2 norm of the difference between measured and modeled signals. Not only the marginal pdf but also its statistics are calculated by numerical evaluation of integrals using the samples selected during importance sampling process of the genetic algorithm. 相似文献
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海上大直径钢管桩打桩过程中,桩周土体受到强烈扰动而发生强度弱化,掌握桩周土体强度弱化规律对于准确预测打桩过程、保证工程安全具有重要意义。为研究土体强度弱化规律,开展了环剪试验模拟打桩对桩周土体的扰动,测试土体强度随剪切速率的变化规律,建立了描述土体强度弱化规律的拟合公式,引入到打桩分析软件中。研究结果表明：土体的强度折减程度不仅与土体本身的性质有关还受到土体的埋深和剪切速率的影响,埋深越深土体强度折减程度越低,剪切速率越高土体强度折减越高,在打桩分析中可采用这里推荐的线性折减方法来模拟不同深度处土体强度的折减规律。 相似文献
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The advanced piston corer (APC) has been used by the Ocean Drilling Program since 1985 for recovering soft sediments from the ocean floor. The pullout force measured on extracting the core barrel from the sediment is shown to correlate with the average shear strength of the sediment core measured in the ship's laboratory. A simple rule of thumb is derived relating the shear strength of the sediment to the pullout force. Multiple APC holes at individual sites allow the consistency of the pullout measurements to be assessed. The effects of different operational procedures during APC coring are also explored. Although generally applicable, the correlation between pullout force and laboratory measurements of shear strength breaks down for some APC holes, possibly because of the disturbance of some sediment types during the APC coring process. A better understanding of the physical process of APC coring, and its effect on the properties of the sediment both inside and immediately outside the core barrel, would indicate what confidence can be put on the measurement of pullout force as a way of evaluating the in situ shear strength of deep sea sediments. 相似文献
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《海洋学报(英文版)》2014,(11):161-F0003
<正>Acta Oceanologica Sinica(AOS)is a comprehensive academic journal edited by the Editorial Committee of Acta Oceanologica Sinica and is designed to provide a forum for important research papers of the marine scientific community which reflect the information on a worldwide basis.The journal publishes scholarly papers on marine science and technology,including physics,chemistry,biology, 相似文献